JPS5812152A - Magnetic recording and reproducing device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is directed to a magnetic recording/reproduction device of a beam-lease drive type.

In the conventional O magnetic recording/reproducing device, the motor is used to
Most of the capstan drive systems use a capstan drive method in which a 1M1 tape is pressed onto the capstan using a pinch roller and then run.

Then, using this method, the number of revolutions of the motor is detected and
I'm playing miiiit.

In contrast, in the capstanless method and the reel drive method, note #1. The magnetic tape speed is detected from the period of the pulses on the magnetic tape by providing a speed detection head consisting of a reproducing head, recording moderate detection pulses on the magnetic tape, and reproducing them. control its speed.

However, with this reel drive system, there were dropouts caused by the adhesion of objects between the magnetic tape and the head and the texture of the magnetic tape. There were drawbacks such as rounding, where appropriate detection pulses could not be obtained, speed control not being applied, and the magnetic tape running out of control (c) or stopping at the part of the leader tape that was missing.

In such a reel drive system, automatic stopping and automatic reversal are performed at the end of the magnetic tape.In addition, conventional methods for detecting the end of a magnetic tape include a combination of one light-emitting element and a light-receiving register. A method for detecting the end of the leader tape, and a reed switch! There is a method to detect the stoppage of the series table.

However, these methods have disadvantages in that they require special parts and circuits, resulting in high costs, and are not reliable.

The object of the present invention is to eliminate the above-mentioned drawbacks, to allow a magnetic tape to run smoothly even in the presence of dropouts, and to enable automatic stop and automatic reversal at the end of the magnetic tape.
K provides a reel drive type magnetic recording/reproducing device which is inexpensive and highly reliable.

In order to achieve the above object, in the present invention, when a speed detection pulse cannot be obtained from the magnetic tape, an oscillator is operated, and the output pulse of the oscillator is sent as a pseudo pulse to the speed control circuit to run the magnetic tape. In addition to maintaining the magnetic tape, the magnetic generator is configured to operate continuously (by detecting the leader tape portion at the end of the tape and automatically stopping and reversing the magnetic tape.

The present invention will be explained below with reference to FIG. W1. FIG. 1 is a block diagram showing an embodiment of a magnetic tape running control system of a magnetic recording/reproducing apparatus according to the present invention. Note that the audio signal recording and reproducing system is omitted.

In the figure, 1 is a recording circuit, 2 is a recording head, 5 is a magnetic tape, 4 is a playback head, 5 is a playback circuit, 6 is an OR circuit, 7 is a speed control circuit, 8 is a detection circuit, 9 is an oscillation circuit, 10 is a count circuit, 11 is a tape running control circuit, T
First, the overall configuration and operation will be briefly described.

When the magnetic tape 5 is in a normal running state, output pulses from the recording circuit 1 are recorded by the recording head 2 onto the magnetic tape s. The recorded speed detection pulse is reproduced by the reproduction head 4.

The recording circuit I passes through the reproduction circuit 5 and the OR circuit 6 and then returns to the recording circuit I.
KFsJ) is also transmitted to the speed control circuit 7, and as a result, a motor (not shown) is controlled by Vt to run the magnetic tape at a predetermined speed.

At a location on the magnetic tape where there is a dropout, the pulse signal from the reproducing circuit 5 is no longer output. This is detected by the detection circuit 8 and the next stage O oscillation circuit 9 is operated. This oscillation circuit 90 is manually powered by the oscillation output company Oraro Road 6.

Therefore, the output of the oscillation circuit 9 is input to the recording circuit 1 and the speed control circuit 7, so that the magnetic tape 5 continues to run without stopping.

& or this dropout part, 9 is the said part 0*
*Now, let's move on to the oscillation circuit after a little while! Since a normal speed detection pulse is applied to the magnetic tape 3 by the output signal of the detection circuit 8, the oscillation of the oscillation circuit 90 is stopped.

Further, when the magnetic tape base travels and reaches the leader tape portion, the oscillation circuit 9 continues to oscillate. Therefore, the count circuit 1o can detect the leader tape part, not the predetermined count circuit OUT part so that the leader tape part can be detected. As a result, the next stage of tape.

Travel control track 11 [tape travel instruction signal TK for automatic stop, automatic reversal, etc. from the side operation switch (not shown)
A corresponding signal can be transmitted to the motor via the speed control circuit 7t.

Next, the main parts of FIG. 1 will be explained in detail.O.
The oscillation may be used or the recording circuit 1 may generate the oscillation.

The recording/reproducing head 2 and the reproducing head 4 are formed, for example, by winding a recording winding and a reproducing winding around two U-shaped cores consisting of a common center core. By forming the gear in this manner, the gear spacing t can be narrowed, so that the frequency of the speed detection pulse can be set high.

As a result, the performance of the speed control circuit 7 can be improved.

Note that in the recording circuit 1, there is a risk that the recording signal may jump from the recording head 2 to the playback head 4 and be reproduced, so in order to reduce the risk of jumping, it is necessary to output the signal with a narrow pulse width. The reproduction circuit 5 is composed of an amplifier and a waveform shaping circuit,
A weak reproduction signal from a reproduction head 4 is amplified and shaped to a level necessary and sufficient as an input to an OR circuit 6 at the next stage. The detection circuit 8 is configured to pass, for example, a reproduction pulse output from the reproduction circuit 5 through an integrating circuit including a resistor and a capacitor to convert it into a DC voltage, and to keep the transistor on with this DC voltage. The detection circuit 8 like this
Because of the configuration, when the reproduction pulse is absent, the transistor switches off, so that the dropout point (or part of the leader tape) can be detected.

The oscillation Ii circuit 9 oscillates at a frequency close to the reproduction pulse, for example, is unstable! multivibrator], the detection circuit 8
connected to the transistor. This makes it easy to start or stop the Wlt-emission. The count circuit 10 outputs an output when a set number of pulses have been counted, and should be set to a number higher than the number of pulses generated by dropouts), and the dropout and leader tape sections. and the leader tape portion can be detected.

For example, in the case of cassette tape, the magnetic tape speed [
Assuming that t-4Jas/j and the gap distance between the recording head 2 and the reproducing head 4 are f50pvs, the frequency of the speed detection pulse proportional to the magnetic tape speed is 4.8av.
/S750μWL" 960H. If this is considered as IKHz for convenience of calculation, one cycle is one cycle of I-C.

Therefore, as a criterion for identifying the dropout and the leader tape section, for example, if a pulse signal is not obtained for more than L5 seconds, it is determined that the dropout is at the leader tape section. t500
By configuring the device to output a signal at a level of 1-cJIil only when (15Iae ÷ 1 wind 7g% 500) is counted, the leader tape portion can be identified and detected from the dropout.

Incidentally, the count circuit 10 can be used as an Atero 1 type that charges a pulse voltage t-container. In this case, the pulse voltage continues to charge the capacitor, and when it rises to a certain voltage value, the reader tape section is identified.
Detectable In addition, the generator m circuit 9 and the count circuit 10 may be formed by integrating KIC or LSI K together with other circuits.

Continuing, the tape running control path 11 is shown in Figure Jl] Details aK
explain.

2nd WA is a block diagram showing an example of the tape running control circuit 11 and its peripheral circuits. In the figure, A is a memory circuit, B is a sequential circuit, and C is a tie! Circuit %D is a logic circuit. A to D forms a tape running control circuit 11. 9 and 12 indicate operation switches. Note that %1
The same parts and parts as those in the figure are indicated by the same reference numerals.

The tape running instruction signal T specified by the operation switch 12 basically controls recording, playback, and stop.

Six types are standard: pause, fast forward, and rewind. In addition, there are various combinations of the above six types, but here the difference is automatic stop after recording and playback (fast forward), automatic stop when rewinding), and recording on one side of magnetic tape ink. Or, after the playback is finished, the tape running is automatically reversed, so that the tape is recorded again and the playback is continued.

The tape running instruction signal T is normal! This can be achieved by using a so-called non-fixed switch, such as a microswitch, whose contacts close only when operated. Therefore, in the memory circuit A,
It is necessary to memorize the tape running instruction signal T until the automatic stop and automatic reversal operations are completed.

Note that this memory circuit A may be constructed from a logic circuit such as a flip-flop.

A sequential circuit (sequence circuit) B is used to control the running of the magnetic tailor 50 in an orderly manner, that is, the drive of a motor (not shown), when the magnetic tape 30 runs in a plurality of running modes such as automatic stop and automatic reversal. It is something. For automatic stop, record f (play) → stop (end of magnetic tape); for automatic reversal, record (play) → stop (end of magnetic tape) → record (play, 4-! reverse) ) in sequence. Note that the sequential circuit B may be configured by arranging as many frits 7vx tubes in parallel as the number of running modes, for example.

The logic i1 circuit is a round circuit that correctly transmits the operation of the sequential circuit B to the speed control circuit 7, and is composed of K, such as at and OR gates.

tft% tie! Circuit C circuit operates with the output of the storage circuit A, and is intended to prevent malfunctions such as automatic stop and automatic reversal at the leader chi 1O portion at the beginning of the magnetic tape. The following explanation will be given using a regenerated portion as an example.

It is assumed that the magnetic tape IK leader tape is played back from the beginning of the tape. In this case, since a speed detection pulse is not obtained, the detection circuit 8 (Figure s1), the oscillation circuit 9, and the count circuit 10 operate to detect the leader tape.

In this case, the operating time of the timer circuit C is determined by the count circuit 1.
0 operates as long as possible, and timer circuit C.
During a certain period of time when the count circuit 1010 is operating, the count circuit 1010
If the logic circuit is configured to inhibit output, the output of the count circuit 10 will not be transmitted to the speed control l1m path 7.

Therefore, at the O leader tape part at the beginning of the 30th volume of the magnetic tape, the leader tape part is rotated while the magnetic tape black continues to run due to the output of the output circuit 9, without any malfunction of automatic stop or automatic reversal. pass. After that, since a speed detection pulse is obtained, the tape is in a normal running state.

Next, at the end of the magnetic tape 3, the timer circuit C does not operate, and the count circuit 10
Detects the part of the magnetic tape leader tape and automatically stops or reverses the running of the magnetic tape.
The a-path I) and the sequential circuit B will operate.

In the case of automatic reversal, when KF and magnetic tape S stop, the timer circuit C is turned on via the logic circuit DK4D memory circuit A, and the tape is reversed and starts running from the leader tape section. Even if the timer circuit C operates again,
Since the above-mentioned operation is repeated, smooth tape running is maintained.

In addition, the above-mentioned memory circuit A, @order circuit B, and timer tix*
You can also replace them all at once with the C circuit, the logic 11 circuit Df, and the microphone W=TY beater, which has recently become widespread. This can be said to be better in terms of strikes, design time, and design changes.

Next, the % speed control circuit will be explained in detail with reference to the drawings.

No.il! 1I is a block diagram showing an example of the speed control circuit 7 and its peripheral circuits. In the same figure, E is the 10th
Amplification circuit, F is waveform shaping circuit %G is happy l Of/l'
(Frequency/voltage) 11 conversion paths, H is a voltage switching circuit, I is a circuit usually composed of an operational amplifier, J is a Hall current circuit, I is a Hall element, L is a second fyf conversion circuit,
M is the 20th increase @gi*%N is the screen-to-wall drive circuit. Said E to N form a speed control path 7. Also, 20
01k indicates the rotor coil, and 21 indicates the rotor of the motor.
sp, the same locations and equivalent parts as in FIG. 1 are indicated by the same reference numerals.

Below, the state of Kamanokori 9 at the time of playback, that is, the magnetic tape 5
Magnetic tape speed from above! The operation of the speed-side m circuit 7 will be explained by explaining the state in which a nine-degree detection pulse is obtained, and also referring to fast forwarding or rewinding, automatic reversal, and automatic stop.

The multiple pulse signals outputted from the OR circuit 6 are amplified to a sufficient voltage value by the amplifier circuit E with an odds ratio of 1 so as to become a rectangular wave by the waveform shaping circuit F at the next stage. Wave y# shaping circuit FO
The output is converted into a DC voltage by the first bf conversion circuit G in the next stage.

An example of this first b-da conversion circuit is a monostable multivibrator that outputs pulses at regular intervals. 1) During the method of triggering and smoothing the output, a constant current is charged (held) by a condenser, A sample hold method may be considered in which the capacitor Y-O charging voltage is discharged according to the cycle of the output of the waveform shaping circuit F.

The output DC voltage (hereinafter referred to as VTAPR) of the first f/V conversion circuit G obtained in this manner is input to the voltage switching circuit HK of the next stage. This voltage switching circuit H has the same function as a mechanical rotary switch. Therefore, during recording or playback, the VTAPE is configured to be output as is according to the control signal output from the tape running control circuit 11.

Next, the signal VTAPR that has passed through the voltage switching circuit Ht is input to the next-stage servo circuit (servo amplifier) 7 (D inverting input terminal. Comparison voltage 1'RE connected to input terminal
It is compared with F and amplified.

This comparison voltage VREF is set to a voltage value corresponding to the normal magnetic tape speed.

Therefore, when the speed of the magnetic chip 13 becomes faster than the normal speed, the VTAPR changes to the VrRE as described later.
Since p becomes higher than F (VTAPE > VREF),
The voltage output from the servo circuit I becomes low. Conversely, when VTAPE<VREF, the output voltage from the servo circuit I becomes high.

Such a servo circuit IO output is input to the Hall energization circuit I. This Hall energizing circuit I is a circuit that applies voltage to the next Hall element K.

When automatic reversal is selected, there is a function of applying a voltage having a polarity opposite to that during recording or reproduction to the Hall element K using a control signal from the tape running control circuit 11).

The Hall element has a function of outputting an output proportional to the input voltage, and the output is applied to the motor coil via the second S amplifier circuit y and the motor drive circuit N, and is applied to the rotor 21.
to drive. vrnx) In the case of VREF (when the magnetic tape speed is faster than the normal speed), the input voltage of the Hall element X becomes low as described above, so the drive voltage that can be applied to the motor coil 20 becomes small. This works to lower the rotational speed of the rotor 21.

Conversely, when VTAPE<VREF (when the magnetic tape speed is slower than the normal speed), the input voltage to the Hall element is not high and acts to increase the rotational speed of the rotor 21. Therefore, the tape running speed during recording or playback (including during automatic reversal recording or playback) is always constant.

On the other hand, when fast forwarding or rewinding according to the control signal from the tape running control circuit 11, the recording head 2
And at the ninth point when the reproducing head 4 leaves the magnetic chip 13,
Cannot obtain speed detection pulse. In this case, the motor is controlled by utilizing the fact that the Hall element K has a function t% of detecting the position of the motor buyer 21, that is, detecting the rotation speed of the rotor 210.

That is, the voltage proportional to the rotation speed of the rotor 210 - the output of the Hall element KO is applied to the second O through the second amplifier M.
Convert it to DC voltage with f conversion circuit and switch to voltage switching circuit HfC.
Enemy input. At that time, the voltage switching circuit H controls the second f by a control signal from the tape running control circuit 11.
It is switched so that only the output of the /conversion circuit LD is applied to the servo circuit I at the next stage.

Note that the voltage proportional to the rotation speed of the rotor 21 mentioned above is
The amplification by the second amplifier M, which inputs the servo circuit IK via the second f/V conversion circuit and the voltage switching circuit H, must match the comparison voltage VREFK.

This is because the VREF is set to a voltage corresponding to the normal magnetic tape speed 1.

It is clear that by adjusting in this manner, the tape running speed during fast forwarding or rewinding can also be kept constant.

Furthermore, in the case of automatic stop, the tape running control circuit 11
In response to the control signal from the motor drive circuit N, energization to the motor coil of the next stage is interrupted. At this time, the recording head 2 and the reproducing head 4 are released from contact with the magnetic tape.

As is clear from the above description, the present invention has the effect of allowing the magnetic tape to run smoothly even if dropouts occur. According to the present invention, an oscillation circuit for running the magnetic tape smoothly despite the presence of the dropouts, and a counting circuit for distinguishing between the dropouts and the leader tape portion are provided. Highly reliable IC or LSIK with circuit.

Can be easily integrated.

Therefore, in order to perform automatic stop and automatic reversal at the end of the magnetic tape, conventional methods for detecting the ON end of the magnetic tape have been adopted, such as a method using a combination of a light emitting element and a light receiving element, and a method using a combination of a reed switch and a magnet. Compared to the method described above, automatic stopping and automatic reversing can be performed at low cost and with high reliability.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the magnetic tape running control system of the magnetic recording/reproducing apparatus of the present invention, FIG. 2 is a block diagram showing an example of the tape running control circuit 11 and its peripheral circuits, and FIG. 2 is a schematic diagram showing an example of a speed control circuit 7 and its peripheral circuits. FIG. 2.-Recording head 5..Magnetic tape 4.-Reproduction head 6..OR circuit 7..Speed control circuit 8..Detection circuit 9..Oscillation circuit
10...Count circuit 11...Tape running control 1@
Road T...Tape running instruction signal t1 diagram

Claims (1)

[Claims] (1) By recording a pulse signal on a magnetic tape (by a Kikama head) and reproducing the pulse signal by a reproducing head, the period of the pulse signal is detected, and based on this, the period of the pulse signal is detected. The magnetic Qi 10 series! A magnetic recording and reproducing device that is controlled by a magnetic recording head includes a detection circuit that detects the presence or absence of the pulse signal, an oscillation circuit whose oscillation is controlled by the output of the detection circuit, and an output of the oscillation circuit and the reproduction head. OR with the output of the nine pulse signals that are reproduced,
An OR circuit that outputs the output pulses to the head and speed control circuit, a count circuit that counts the number of output signals from the oscillation circuit and outputs a signal when the scheduled number has been counted, and an automatic stop and automatic reversal circuit. a tape running control circuit that controls and outputs a tape running instruction signal including an instruction signal according to the output signal of the count circuit; The control circuit operates according to the instructions of the control signal.
What is claimed is: 1. A magnetic recording reproduction device characterized by comprising a speed control circuit for controlling rotation of a motor.